[llvm] r268847 - Refactor stripDebugInfo(Function) to handle intrinsic

Mehdi Amini via llvm-commits llvm-commits at lists.llvm.org
Mon May 9 14:31:27 PDT 2016


> On May 9, 2016, at 2:17 PM, Adrian Prantl <aprantl at apple.com> wrote:
> 
>> 
>> On May 6, 2016, at 9:10 PM, Mehdi Amini via llvm-commits <llvm-commits at lists.llvm.org> wrote:
>> 
>> Author: mehdi_amini
>> Date: Fri May  6 23:10:52 2016
>> New Revision: 268847
>> 
>> URL: http://llvm.org/viewvc/llvm-project?rev=268847&view=rev
>> Log:
>> Refactor stripDebugInfo(Function) to handle intrinsic
>> 
>> This moves the code that handles stripping debug info intrinsic from
>> StripDebugInfo(Module) to StripDebugInfo(Function). The latter is
>> already walking every instructions so it makes sense to do it at the
>> same time.
>> This makes also stripDebugInfo(Function) as an API more useful: it
>> is really dropping every debug info in the Function.
>> Finally the existing code is trigerring an assertion when the Module
>> is not fully materialized.
>> 
> 
> Thanks!
> 
> 
>> From: Mehdi Amini <mehdi.amini at apple.com>
>> 
>> Added:
>>   llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.bc
>>   llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.ll
>>   llvm/trunk/test/ThinLTO/X86/drop-debug-info.ll
>> Modified:
>>   llvm/trunk/lib/IR/DebugInfo.cpp
>>   llvm/trunk/test/Transforms/StripSymbols/2010-06-30-StripDebug.ll
>> 
>> Modified: llvm/trunk/lib/IR/DebugInfo.cpp
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DebugInfo.cpp?rev=268847&r1=268846&r2=268847&view=diff
>> ==============================================================================
>> --- llvm/trunk/lib/IR/DebugInfo.cpp (original)
>> +++ llvm/trunk/lib/IR/DebugInfo.cpp Fri May  6 23:10:52 2016
>> @@ -247,8 +247,21 @@ bool llvm::stripDebugInfo(Function &F) {
>>    Changed = true;
>>    F.setSubprogram(nullptr);
>>  }
>> +
>> +  Function *Declare = F.getParent()->getFunction("llvm.dbg.declare");
>> +  Function *DbgVal = F.getParent()->getFunction("llvm.dbg.value");
>>  for (BasicBlock &BB : F) {
>> -    for (Instruction &I : BB) {
>> +    for (auto II = BB.begin(), End = BB.end(); II != End;) {
>> +      Instruction &I = *II++; // We may delete the instruction, increment now.
>> +      // Remove all of the calls to the debugger intrinsics, and remove them
>> +      // from the module.
>> +      CallInst *CI = dyn_cast<CallInst>(&I);
>> +      if (CI && CI->getCalledFunction() &&
>> +          (CI->getCalledFunction() == Declare ||
>> +           CI->getCalledFunction() == DbgVal)) {
> 
> 
> This makes me wonder: Could we achieve the same thing by testing for isa<DbgInfoIntrinsic>() and would it be more efficient?

At least it would be "nicer", I didn't know about this class (DbgInfoIntrinsic). Are there other "DbgInfoIntrinsic" than the two handled here? (i.e. would it be a semantic change).

-- 
Mehdi


> 
> -- adrian
> 
>> +        CI->eraseFromParent();
>> +        Changed = true;
>> +      }
>>      if (I.getDebugLoc()) {
>>        Changed = true;
>>        I.setDebugLoc(DebugLoc());
>> @@ -261,26 +274,6 @@ bool llvm::stripDebugInfo(Function &F) {
>> bool llvm::StripDebugInfo(Module &M) {
>>  bool Changed = false;
>> 
>> -  // Remove all of the calls to the debugger intrinsics, and remove them from
>> -  // the module.
>> -  if (Function *Declare = M.getFunction("llvm.dbg.declare")) {
>> -    while (!Declare->use_empty()) {
>> -      CallInst *CI = cast<CallInst>(Declare->user_back());
>> -      CI->eraseFromParent();
>> -    }
>> -    Declare->eraseFromParent();
>> -    Changed = true;
>> -  }
>> -
>> -  if (Function *DbgVal = M.getFunction("llvm.dbg.value")) {
>> -    while (!DbgVal->use_empty()) {
>> -      CallInst *CI = cast<CallInst>(DbgVal->user_back());
>> -      CI->eraseFromParent();
>> -    }
>> -    DbgVal->eraseFromParent();
>> -    Changed = true;
>> -  }
>> -
>>  for (Module::named_metadata_iterator NMI = M.named_metadata_begin(),
>>         NME = M.named_metadata_end(); NMI != NME;) {
>>    NamedMDNode *NMD = &*NMI;
>> 
>> Added: llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.bc
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.bc?rev=268847&view=auto
>> ==============================================================================
>> Binary files llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.bc (added) and llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.bc Fri May  6 23:10:52 2016 differ
>> 
>> Added: llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.ll?rev=268847&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.ll (added)
>> +++ llvm/trunk/test/ThinLTO/X86/Inputs/drop-debug-info.ll Fri May  6 23:10:52 2016
>> @@ -0,0 +1,47 @@
>> +; This file is checked-in as a .bc file, because the debug info version is
>> +; intentionally out-of-date and llvm-as will drop it before writing the bitcode
>> +
>> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
>> +target triple = "x86_64-apple-macosx10.11.0"
>> +
>> +
>> + at argc = global i8 0, align 1
>> +
>> +define void @globalfunc() {
>> +entry:
>> +  %0 = load i8, i8* @argc, align 1
>> +  tail call void @llvm.dbg.value(metadata i8 %0, i64 0, metadata !19, metadata !29), !dbg !DILocation(scope: !13)
>> +  ret void
>> +}
>> +
>> +
>> +declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
>> +
>> +!llvm.dbg.cu = !{!0}
>> +!llvm.module.flags = !{!22, !23}
>> +
>> +!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, enums: !2, retainedTypes: !3, globals: !20, imports: !2, emissionKind: FullDebug)
>> +!1 = !DIFile(filename: "test.cpp", directory: "")
>> +!2 = !{}
>> +!3 = !{!4}
>> +!4 = !DICompositeType(tag: DW_TAG_class_type, name: "C", line: 2, size: 8, align: 8, file: !1, elements: !5, identifier: "_ZTS1C")
>> +!5 = !{!6}
>> +!6 = !DISubprogram(name: "test", file: !1, scope: !4, type: !7, isDefinition: false)
>> +!7 = !DISubroutineType(types: !8)
>> +!8 = !{!9, !10, !11, !11, !11, null}
>> +!9 = !DIBasicType(encoding: DW_ATE_signed, size: 32, align: 32, name: "int")
>> +!10 = !DIDerivedType(baseType: !4, tag: DW_TAG_pointer_type, size: 64, align: 64, flags: DIFlagArtificial)
>> +!11 = !DIBasicType(tag: DW_TAG_base_type, name: "char", size: 8, align: 8, encoding: DW_ATE_signed_char)
>> +!13 = distinct !DISubprogram(name: "test_with_debug", linkageName: "test_with_debug", line: 6, isLocal: false, isDefinition: true, flags: DIFlagPrototyped, isOptimized: true, unit: !0, scopeLine: 6, file: !1, scope: !14, type: !15, variables: !17)
>> +!14 = !DIFile(filename: "test.cpp", directory: "")
>> +!15 = !DISubroutineType(types: !16)
>> +!16 = !{null}
>> +!17 = !{!18, !19}
>> +!18 = !DILocalVariable(name: "c", line: 7, scope: !13, file: !14, type: !4)
>> +!19 = !DILocalVariable(name: "lc", line: 8, scope: !13, file: !14, type: !11)
>> +!20 = !{!21}
>> +!21 = !DIGlobalVariable(name: "argc", line: 1, isLocal: false, isDefinition: true, scope: null, file: !14, type: !11, variable: i8* @argc)
>> +!22 = !{i32 2, !"Dwarf Version", i32 4}
>> +!23 = !{i32 2, !"Debug Info Version", i32 0}
>> +!25 = !DILocation(line: 8, column: 3, scope: !13)
>> +!29 = !DIExpression()
>> 
>> Added: llvm/trunk/test/ThinLTO/X86/drop-debug-info.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/ThinLTO/X86/drop-debug-info.ll?rev=268847&view=auto
>> ==============================================================================
>> --- llvm/trunk/test/ThinLTO/X86/drop-debug-info.ll (added)
>> +++ llvm/trunk/test/ThinLTO/X86/drop-debug-info.ll Fri May  6 23:10:52 2016
>> @@ -0,0 +1,20 @@
>> +; RUN: opt -module-summary %s -o %t.bc
>> +; RUN: llvm-lto -thinlto-action=thinlink -o %t.index.bc %t.bc %p/Inputs/drop-debug-info.bc
>> +
>> +; The imported module has out-of-date debug information, let's make sure we can
>> +; drop them without crashing when materializing later.
>> +; RUN: llvm-lto -thinlto-action=import %t.bc -thinlto-index=%t.index.bc -o - | llvm-dis -o - | FileCheck %s
>> +; CHECK: define available_externally void @globalfunc
>> +; CHECK-NOT: llvm.dbg.value
>> +
>> +target datalayout = "e-m:o-i64:64-f80:128-n8:16:32:64-S128"
>> +target triple = "x86_64-apple-macosx10.11.0"
>> +
>> +
>> +define i32 @main() #0 {
>> +entry:
>> +  call void (...) @globalfunc()
>> +  ret i32 0
>> +}
>> +
>> +declare void @globalfunc(...)
>> \ No newline at end of file
>> 
>> Modified: llvm/trunk/test/Transforms/StripSymbols/2010-06-30-StripDebug.ll
>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/StripSymbols/2010-06-30-StripDebug.ll?rev=268847&r1=268846&r2=268847&view=diff
>> ==============================================================================
>> --- llvm/trunk/test/Transforms/StripSymbols/2010-06-30-StripDebug.ll (original)
>> +++ llvm/trunk/test/Transforms/StripSymbols/2010-06-30-StripDebug.ll Fri May  6 23:10:52 2016
>> @@ -1,6 +1,6 @@
>> ; RUN: opt -strip-debug < %s -S | FileCheck %s
>> 
>> -; CHECK-NOT: llvm.dbg
>> +; CHECK-NOT: call void @llvm.dbg.value
>> 
>> @x = common global i32 0                          ; <i32*> [#uses=0]
>> 
>> 
>> 
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